The toylot company makes an electric train with a motor that it claims will draw an average of only 0.8 ampere (a) under a normal load. a sample of nine motors was tested, and it was found that the mean current was x = 1.32 a, with a sample standard deviation of s = 0.44 a.

do the data indicate that the toylot claim of 0.8 a is too low? (use a 1% level of significance.)

The data indicate that toylot claim   t(s)  =  -  3,54

Step-by-step explanation:

T student distribution

sample size   n  = 9      df =  n  -  1    df  =  9  -  1    df  = 8

sample mean     μ  =  1.32

sample standard deviation     σ   =  0,44

1.- Test  hypothesis      

H₀           null hypothesis        μ₀  =    0,8

Hₐ   alternative hypothesis    μ₀  <    0,8

2.- Critical value

Confidence interval   99 %        α  =  0,01    and  df  =  8

t(c)  = - 2.8965      

3.-Compute t(s)

t(s)  =  [  (  μ  -   μ₀  ) / s/√n ]     t(s)  =  - 0,52 * 3/ 0,44      t(s)  = - 3.54

4.- Compare  t(s)   and  t(c)

t(s) is far away in the rejection region. The data indicate that toylot claim is too low